1. skin
お肌が若くなるんでしょ？Your skin will get younger, right?
2. body (in the context of intimate bodily contact)
寒い夜、二人は肌を寄せ合って眠った。On the cold night, the two of them slept huddled close together.
3. surface; grain (e.g. of wood); texture
4. disposition; temperament; character; type